An intake system for a multi-cylinder engine typically includes an intake manifold constituted by branch pipes respectively communicating with intake ports of corresponding cylinders, an intake chamber (intake air collecting portion) communicating with each branch pipe, and an intake air introduction pipe communicating with the intake chamber. In such an intake system, there is a problem that since each branch pipe is joined to a side of a cylinder head substantially perpendicularly thereto, the branch pipes tend to protrude to the side of the engine and increase the external dimension of the entire engine. To solve such a problem, there is proposed an intake system in which each branch pipe extends to curve upward (toward the head cover) from the downstream end to the upstream end, thereby to place the air intake chamber close to the head cover and make the entire engine compact (for example, see patent document 1).